Promoting the re-vegetation of disturbed pit and quarry soil using wastewater-treated Grodan rockwool as a nitrogen and phosphorus source

Abstract

The disturbed soils of former aggregate mining sites in Ontario can vary in texture, moisture retention, and fertility complicating efforts for re-vegetation. Grodan® rockwool, untreated (GRW) or treated with wastewater (GRW-AWW), was installed in stony and silt-loam soil, to determine if this amendment could help maintain moisture, provide plant-available nitrogen (N) and phosphorus (P) to perennial ryegrass (Lolium perenne L.), and reduce N and P leaching. A zone of GRW in stony soil demonstrated a mean higher volumetric water content percent (VWC%) than the control. The mean length of perennial ryegrass, grown in stony soil treated with GRW-AWW, were 0.99 cm longer than the control. A zone of saturated GRW was found to significantly reduce ammonium leaching in silt-loam soil. The rate of GRW’s degradability was undetermined. Wastewater-treated GRW may be useful as a soil amendment, however, more research is needed to establish GRW’s persistence and interaction with soil properties.